Method and system for optimizing CO2 adsorption performance of COF material based on molecular simulation

Abstract

The invention relates to the technical field of CO2 adsorption performance optimization, in particular to a COF material CO2 adsorption performance optimization method and system based on molecular simulation, and the method comprises the steps: selecting a basic COF material with a straight-through pore channel, and determining working conditions required by simulation; on the basis of the selected COF material and working conditions required by simulation, constructing a candidate model of a gradient modification molecular model; based on the candidate model, calculating an efficiency index by adopting molecular simulation, and quantifying the comprehensive adsorption performance of the candidate model under the anti-interference condition; carrying out iterative optimization by changing gradient design parameters, and screening out an optimized gradient modification molecular model to obtain an optimized gradient scheme; and carrying out dynamic simulation on the optimized gradient scheme, verifying the effect of the gradient function, and outputting a guidance specification. According to the CO2 adsorption performance optimization method provided by the invention, the problem that an existing uniform modification technology cannot synergistically realize efficient CO2 capture and strong water vapor interference resistance under high-temperature and high-humidity severe working conditions is solved.

Description

Technical Field

[0001] This application relates to the field of CO2 adsorption performance optimization technology, and in particular to a method and system for optimizing the CO2 adsorption performance of COF materials based on molecular simulation. Background Technology

[0002] Molecular simulation is a key technology that uses computer models to simulate the structure and behavior of matter at the atomic and molecular scale. COF, or covalent organic framework materials, are a class of novel porous crystalline materials with regular pore structures formed by the precise connection of organic molecular units through strong covalent bonds. CO2 adsorption refers to the process of selectively capturing and enriching carbon dioxide gas using the physical or chemical interactions on the surface of porous materials. Combining these three technologies—namely, using molecular simulation to design and optimize the molecular structure of COF materials in a computer—allows for a deeper understanding and precise control of their interaction mechanisms with CO2 molecules. This provides crucial theoretical basis and design strategies for guiding the synthesis of high-performance carbon dioxide adsorbents.

[0003] In natural gas pretreatment, particularly on space-constrained and harsh environments like offshore platforms, solid adsorbents such as COF materials show great potential due to their high specific surface area and tunable pore structure. However, the CO2 adsorption performance of these materials significantly deteriorates in feed gases containing high temperature, high humidity, and water vapor. This is mainly because existing material modification techniques mostly focus on improving the adsorption capacity of individual CO2 molecules or overall hydrophobicity by uniformly introducing functional groups, failing to address the problem of competitive adsorption of water molecules at the molecular scale. Water molecules can co-occupy or even block the pores and active sites of the material with CO2, leading to a sharp decline in the material's effective adsorption capacity and selectivity, thus limiting the reliability and economic viability of this technology in harsh environments.

[0004] In existing technologies, some studies have attempted to optimize the performance of adsorption materials through molecular simulation. For example, existing technologies disclose a method for screening VOCs adsorbents based on molecular simulation. This method constructs models of molecular sieves, VOCs, nitrogen, and water molecules, and combines quantum chemical optimization with Monte Carlo simulation to screen for the optimal adsorbent structure. Although this method has made significant progress in the field of VOCs adsorption, it focuses on the uniform modification and cation regulation of molecular sieve materials. It does not address the problem of CO2 adsorption performance degradation of COF materials due to water vapor interference under high temperature and high humidity environments, nor does it propose a solution for gradient functionalization design of pore structure.

[0005] Therefore, in order to address the problem that existing uniform modification technologies cannot achieve efficient CO2 capture and strong resistance to water vapor interference under harsh conditions of high temperature and high humidity, it is urgent to develop a design method for COF materials based on molecular simulation that can guide the construction of gradient functionalized pore structures, so as to improve their comprehensive adsorption performance under real working conditions. Summary of the Invention

[0006] This application provides a method and system for optimizing the CO2 adsorption performance of COF materials based on molecular simulation. It can guide the synthesis of COF materials with a continuous change from hydrophobic water to high CO2 affinity domain within the pores, solving the problem that existing uniform modification techniques cannot synergistically achieve efficient CO2 capture and strong resistance to water vapor interference under harsh conditions of high temperature and high humidity.

[0007] To address the aforementioned technical problems, in a first aspect, embodiments of this application provide a method for optimizing the CO2 adsorption performance of COF materials based on molecular simulation, comprising the following steps: Step S1, selecting a basic COF material with through-holes and defining the operating conditions required for simulation; Step S2, constructing candidate models for gradient-modified molecular models based on the selected COF material and the operating conditions required for simulation; Step S3, calculating performance indicators using molecular simulation based on the candidate models and quantifying their comprehensive adsorption performance under anti-interference conditions; Step S4, iteratively optimizing by changing gradient design parameters to select optimized gradient-modified molecular models and obtain optimized gradient schemes; Step S5, dynamically simulating the optimized gradient schemes to verify the effectiveness of the gradient function and outputting a guidance manual.

[0008] In some exemplary embodiments, a base COF material with through-holes is selected, and the operating conditions required for simulation are defined, including: selecting a base COF model with a one-dimensional through-hole structure, and using the atomic coordinates, bonding relationships, and lattice parameters of the base COF model as the initial input structure for simulation; defining the operating environment parameters of high temperature, high humidity, and mixed gas required for simulation to reflect the harsh conditions of the offshore platform pretreatment unit.

[0009] In some exemplary embodiments, the basic COF model includes a model that mimics COF-1 with pore sizes between 1.5 nm and 3.0 nm.

[0010] In some exemplary embodiments, based on the selected COF material and the operating conditions required for simulation, a candidate model for a gradient-modified molecular model is constructed, including: defining the axial direction of the pores on the selected basic COF framework as the Z direction; dividing the entire pores into N consecutive intervals along the Z axis, each interval representing a domain with a different degree of functionalization; defining different functional group modification strategies for each interval i; and constructing a COF crystal model with a gradient functionalization distribution, from the strongly hydrophobic functional region at the entrance to the high CO2 affinity functional region inside, through atomic substitution or addition in molecular simulation software.

[0011] In some exemplary embodiments, different functional group modification strategies are defined for each interval i, including: for interval i=1: modification is performed using high-density hydrophobic functional groups, with modification density... Set to maximum value For the middle interval Density of functional group modifications from Decrease linearly or exponentially to a lower value; for the interval i=N: modify with functional groups that have a strong affinity for CO2, with the density set to .

[0012] In some exemplary embodiments, the performance indicators include: the CO2 adsorption capacity, selectivity, and water adsorption capacity of the material; the performance indicators are calculated using molecular simulation, including: using the giant canonical Monte Carlo molecular simulation method, performing adsorption simulations on the basic COF material defined in step S1 under defined operating conditions, and on the candidate model constructed in step S2; after the simulation reaches equilibrium, the absolute adsorption capacity of CO2 in the COF material is statistically analyzed. The absolute adsorption capacity of water molecules in COF materials And calculate the CO2 / CH4 selectivity. Define the gradient functional synergistic efficiency index This is used to quantify the overall performance of gradient design under harsh operating conditions. The calculation formula is as follows: (Calculated in the simulation results analysis step)

[0013] In the formula, and These represent the adsorption amounts of CO2 and H2O, respectively. This refers to the selectivity of CO2 for CH4; It is a positive number between 0.01 and 0.1, used to prevent the denominator from being zero.

[0014] In some exemplary embodiments, by changing the gradient design parameters and performing iterative optimization, optimized gradient-modified molecular models are selected to obtain optimized gradient schemes. This includes: changing the gradient functionalization parameters in step S2 to generate new candidate models. The changed parameters include, but are not limited to: the number of gradient intervals N; the combination of functional group types in each interval; and the modification density distribution curve of functional groups in each interval. For each new candidate model, step S3 is repeated to calculate its corresponding synergistic efficacy index. Compare all candidate models Value, selection The candidate model that reaches the maximum value is the optimized gradient-modified molecular model. The gradient functional parameter corresponding to the maximum value is determined as the optimized gradient scheme.

[0015] In some exemplary embodiments, dynamic simulations are performed on the optimized gradient scheme to verify the effectiveness of the gradient function, including: performing additional molecular dynamics simulations on the optimized gradient-modified molecular model for several nanoseconds to observe the dynamic behavior of gas molecules within the pores; and verifying the effectiveness of the gradient function by analyzing the trajectory files from the molecular dynamics simulations.

[0016] In some exemplary embodiments, verifying the effect of the gradient function includes: observing whether water molecules are indeed confined to the hydrophobic region at the pore inlet and have difficulty diffusing into the pore interior; and observing whether CO2 molecules can pass smoothly through the hydrophobic region at the inlet and accumulate in the high affinity region of amino / amidinyl groups deep within the pore.

[0017] Secondly, this application also provides a molecular simulation-based COF material CO2 adsorption performance optimization system. This system is used to implement the molecular simulation-based COF material CO2 adsorption performance optimization method as described in the above embodiments, comprising: a material and operating condition definition module, a gradient model construction module, an efficiency index calculation module, an iterative optimization module, and a verification and output module connected sequentially. The material and operating condition definition module is used to select a basic COF material with through-holes and define the operating conditions required for simulation. The gradient model construction module is used to construct candidate models of gradient-modified molecular models based on the selected COF material and the required operating conditions for simulation. The efficiency index calculation module is used to calculate the efficiency index using molecular simulation based on the candidate models and quantify their comprehensive adsorption performance under anti-interference conditions. The iterative optimization module is used to perform iterative optimization by changing gradient design parameters, screen out optimized gradient-modified molecular models, and obtain optimized gradient schemes. The verification and output module is used to dynamically simulate the optimized gradient scheme, verify the effect of the gradient function, and output a guidance manual.

[0018] The technical solution provided in this application has at least the following advantages: This application provides a method and system for optimizing the CO2 adsorption performance of COF materials based on molecular simulation. The method includes the following steps: Step S1, selecting a basic COF material with through-holes and defining the operating conditions required for simulation; Step S2, constructing candidate models of gradient-modified molecular models based on the selected COF material and the operating conditions required for simulation; Step S3, calculating the performance index using molecular simulation based on the candidate models and quantifying their comprehensive adsorption performance under anti-interference conditions; Step S4, iteratively optimizing by changing the gradient design parameters to select the optimized gradient-modified molecular model and obtain the optimized gradient scheme; Step S5, dynamically simulating the optimized gradient scheme to verify the effect of the gradient function and outputting a guidance manual.

[0019] This application constructs a gradient functionalized structure from hydrophobic domains to high-affinity domains, enabling COF materials to exhibit excellent anti-interference performance when facing high-temperature and high-humidity mixed gases. The high-density hydrophobic modification at the pore inlet effectively blocks the penetration of water molecules into the pore interior, reducing the competitive adsorption of water molecules by internal high-affinity sites. This allows the active sites inside the material dedicated to CO2 adsorption to remain clean and efficient in humid environments. Therefore, the material designed according to this method exhibits a more stable adsorption capacity in practical applications, reduces the pretreatment requirements for deep drying of the feed gas, simplifies the process flow, and reduces operating costs.

[0020] This application achieves precise control over the diffusion path and adsorption sites of gas molecules through gradient design guided by molecular simulation. The hydrophobic inlet region repels water molecules while offering minimal obstruction to smaller CO2 molecules, allowing them to rapidly penetrate deep into the pores. Meanwhile, the dense high-affinity functional groups deep within the pores strongly capture CO2, ensuring high adsorption selectivity. This synergistic mechanism of rapid inlet passage and strong internal capture enables the material to maintain high CO2 / CH4 selectivity without sacrificing its adsorption kinetics. The resulting material exhibits a faster adsorption rate and more efficient site utilization, thereby enabling the adsorption tower device to achieve higher processing efficiency in the periodic adsorption-desorption cycle. Attached Figure Description

[0021] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments, and unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0022] Figure 1 This is a schematic flowchart illustrating a method for optimizing the CO2 adsorption performance of COF materials based on molecular simulation, provided in an embodiment of this application.

[0023] Figure 2This is a schematic diagram of the module structure of a COF material CO2 adsorption performance optimization system based on molecular simulation provided in an embodiment of this application. Detailed Implementation

[0024] As can be seen from the background technology, the existing technology mainly focuses on the uniform modification and cation regulation of molecular sieve materials, without addressing the problem of CO2 adsorption performance degradation caused by water vapor interference in high temperature and high humidity environments, nor has it proposed a solution for gradient functionalization design of pore structure.

[0025] Therefore, in order to address the problem that existing uniform modification technologies cannot achieve efficient CO2 capture and strong resistance to water vapor interference under harsh conditions of high temperature and high humidity, it is urgent to develop a design method for COF materials based on molecular simulation that can guide the construction of gradient functionalized pore structures, so as to improve their comprehensive adsorption performance under real working conditions.

[0026] To address the aforementioned technical problems, this application provides a method and system for optimizing the CO2 adsorption performance of COF materials based on molecular simulation, comprising the following steps: Step S1, selecting a basic COF material with through-holes and defining the operating conditions required for simulation; Step S2, constructing candidate models for gradient-modified molecular models based on the selected COF material and the operating conditions required for simulation; Step S3, calculating performance indicators using molecular simulation based on the candidate models and quantifying their comprehensive adsorption performance under anti-interference conditions; Step S4, iteratively optimizing by changing gradient design parameters to select optimized gradient-modified molecular models and obtain optimized gradient schemes; Step S5, dynamically simulating the optimized gradient schemes to verify the effectiveness of the gradient function and outputting a guidance manual. This application, by constructing a gradient functionalization design method based on molecular simulation, can guide the synthesis of COF materials with continuously varying domains from hydrophobic water to high CO2 affinity within the pores, solving the problem that existing uniform modification techniques cannot synergistically achieve efficient CO2 capture and strong resistance to water vapor interference under harsh conditions of high temperature and high humidity.

[0027] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0028] See Figure 1 This application provides a method and system for optimizing the CO2 adsorption performance of COF materials based on molecular simulation, including the following steps: Step S1: Select a basic COF material with a straight channel and define the working conditions required for simulation.

[0029] Step S2: Based on the selected COF material and the operating conditions required for simulation, construct candidate models for gradient-modified molecular models.

[0030] Step S3: Based on the candidate model, use molecular simulation to calculate the performance index and quantify its comprehensive adsorption performance under anti-interference conditions.

[0031] Step S4: By changing the gradient design parameters, iterative optimization is performed to select the optimal gradient-modified molecular model and obtain the optimal gradient scheme.

[0032] Step S5: Perform dynamic simulation on the optimized gradient scheme to verify the effect of the gradient function and output the instruction manual.

[0033] In some embodiments, step S1 involves selecting a base COF material with a through-hole and specifying the required operating conditions for simulation, including: Step S101: Select a basic COF model with a one-dimensional through-hole structure, and use the atomic coordinates, bonding relationships and lattice parameters of the basic COF model as the initial input structure for the simulation.

[0034] Step S102: Define the operating environment parameters for high temperature, high humidity and mixed gas required for simulation to reflect the harsh conditions of the offshore platform pretreatment unit.

[0035] The stringent condition in step S102 is: temperature. (50°C); Pressure (Ambient pressure adsorption); Gas composition (mole fraction): (Simulating wet natural gas containing 2% water vapor).

[0036] In some embodiments, the basic COF model in step S1 includes a model that mimics COF-1, with a pore size between 1.5 nm and 3.0 nm.

[0037] In some embodiments, step S2 involves constructing a candidate model for the gradient-modified molecular model based on the selected COF material and the operating conditions required for the simulation, including: Step S201: On the selected basic COF skeleton, define the axis of its channel as the Z direction; divide the entire channel along the Z axis into N (e.g., N=5) consecutive intervals, each interval representing a domain with a different degree of functionalization.

[0038] Step S202: Define different functional group modification strategies for each interval i.

[0039] Step S203: In molecular simulation software, by replacing or adding atoms, construct a COF crystal model with a gradient functionalization distribution, from the strongly hydrophobic functional region at the entrance to the high CO2 affinity functional region inside.

[0040] In some embodiments, step S202 involves each interval i ( Define different functional group modification strategies, including: For interval i=1: modification with high-density hydrophobic functional groups (e.g., trifluoromethyl (-CF3) or benzene rings), modification density... Set to maximum value .

[0041] For the middle interval Density of functional group modifications from It decreases linearly or exponentially to a lower value.

[0042] For the interval i=N (deepest point of the channel): Modification is performed using high-density functional groups with a strong affinity for CO2, such as amine (-NH2) or amidine groups, with a density set to... .

[0043] In some embodiments, performance indicators include: CO2 adsorption capacity, selectivity, and water adsorption capacity of the material; the performance indicators are calculated using molecular simulation, including: using the grand canonical Monte Carlo (GCMC) molecular simulation method, performing adsorption simulations on the basic COF material (mixed gas (CO2 / CH4 / H2O)) defined in step S1 under defined operating conditions, and the candidate model constructed in step S2; after the simulation reaches equilibrium, the absolute adsorption capacity of CO2 in the COF material is statistically analyzed. The absolute adsorption capacity of water molecules in COF materials And calculate the CO2 / CH4 selectivity. Define the gradient functional synergistic efficiency index This is used to quantify the overall performance of gradient design under harsh operating conditions. The calculation formula is as follows: (Calculated in the simulation results analysis step)

[0044] In the formula, and These represent the adsorption amounts of CO2 and H2O, respectively. This refers to the selectivity of CO2 for CH4; It is a small positive number (e.g., 0.01 to 0.1) to prevent the denominator from being zero and to balance the dimensions.

[0045] In some embodiments, by changing the gradient design parameters and performing iterative optimization, optimized gradient-modified molecular models are selected to obtain optimized gradient schemes. This includes: changing the gradient functionalization parameters in step S2 to generate new candidate models. The changed parameters include, but are not limited to: the number of gradient intervals N; the combination of functional group types in each interval (e.g., trying -CF3 and benzene ring in the entry region, and trying -NH2 and amidine in the deep region); the modification density distribution curve of functional groups in each interval; and repeating step S3 for each new candidate model to calculate its corresponding synergistic efficiency index. Compare all candidate models Value, selection The candidate model that reaches the maximum value is the optimized gradient-modified molecular model. The gradient functionalization parameter (functional group type, density distribution, etc.) corresponding to the maximum value is determined as the optimal gradient scheme.

[0046] In some embodiments, dynamic simulations are performed on the optimized gradient scheme to verify the effectiveness of the gradient function, including: performing additional molecular dynamics simulations on the optimized gradient-modified molecular model for several nanoseconds to observe the dynamic behavior of gas molecules within the pores; and verifying the effectiveness of the gradient function by analyzing the trajectory files from the molecular dynamics simulations.

[0047] In some embodiments, verifying the effect of the gradient function includes: observing whether water molecules are indeed confined to the hydrophobic region at the pore inlet and have difficulty diffusing into the pore interior; and observing whether CO2 molecules can pass smoothly through the hydrophobic region at the inlet and accumulate in the high affinity region of amino / amidinyl groups deep within the pore.

[0048] The following section provides a detailed introduction to the method for optimizing the CO2 adsorption performance of COF materials based on molecular simulation, as provided in this application, through specific application examples.

[0049] This embodiment demonstrates how to use the aforementioned molecular simulation-based optimization method to design a covalent organic framework (COF) material with high adsorption performance and selectivity for CO2 under high temperature and high humidity conditions.

[0050] Step 1: Goal definition and model building.

[0051] First, a basic COF structure with large one-dimensional channels, approximately 2.8 nm in diameter, was selected, similar in structure to COF-108. This basic structure is defined as Base-COF. The simulation conditions were set to simulate the high-temperature, high-humidity feed gas in front of the dehydration tower of an offshore platform. temperature: .

[0052] Total pressure: .

[0053] Gas composition (mole fraction): .

[0054] Next, a gradient functionalization model is constructed. The length of a single cell in the Base-COF (approximately 3.4 nm along the pore direction) is defined as the gradient region, and it is divided into N=3 consecutive intervals: Interval 1 ( All available modification sites within this range were modified with hydrophobic -C(CH3)3 (tert-butyl) functional groups, with a modification density of [missing information]. .

[0055] Interval 2 ( This region undergoes no functional group modification, preserving the original surface chemistry of the Base-COF, and the modification density... ; Interval 3 ( All available modification sites within this range were modified with -NH2 (amino) functional groups that have a high affinity for CO2, and the modification density was [not specified]. .

[0056] This model is named Gradient-COF-1.

[0057] Step 2: Constructing the comparison model.

[0058] To highlight the advantages of this method, this embodiment also constructs two comparative models: Uniform-Hydrophobic-COF: The entire pore is modified with 100% density -C(CH3)3 functional groups; Uniform-Amine-COF: The entire pore is modified with 100% density -NH2 functional groups; Step 3: Molecular simulation and performance evaluation.

[0059] The giant canonical Monte Carlo (GCMC) simulation method was used to simulate mixed gas adsorption for all three models (Gradient-COF-1, Uniform-Hydrophobic-COF, Uniform-Amine-COF) under the operating conditions defined above. Each simulation system contained at least 2×2×2 unit cells to ensure negligible size effects, and the number of simulation steps exceeded 1×10⁻⁶. 7 Take steps to ensure adequate balance.

[0060] After the simulation was completed, equilibrium adsorption data were collected, and key performance indicators were calculated, as shown in Table 1: Table 1 Calculation results of key performance indicators for each model

[0061] Synergy Effectiveness Index The calculation formula is , where constant Used to prevent the denominator from being zero.

[0062] Step 4: Results Analysis and Mechanism Verification.

[0063] Table 1 clearly shows that while Uniform-Amine-COF exhibits the highest CO2 adsorption capacity and selectivity, its water adsorption capacity is extremely high (22.40 mol / kg). This indicates that under high humidity conditions, its pores are largely occupied by water molecules, severely hindering CO2 adsorption and potentially leading to hydrolytic deactivation of the material structure. Uniform-Hydrophobic-COF has a low water adsorption capacity, but its CO2 adsorption capacity and selectivity are also significantly low because its surface lacks sites for specific CO2 interactions. The Gradient-COF-1 designed in this embodiment achieves the best overall performance. While maintaining a high CO2 adsorption capacity (2.85 mol / kg) and selectivity (25.3), it successfully suppresses water adsorption to a low level (5.10 mol / kg). This directly results in a lower synergistic efficiency index. It reached 14.1, far exceeding the two comparative models.

[0064] To verify the mechanism of its gradient function, this application performed additional molecular dynamics (MD) simulations on Gradient-COF-1. Trajectory analysis from the simulations shows: Water molecules do tend to cluster near the pore entrance (interval 1), but due to strong hydrophobicity, the energy barrier for their diffusion into the pore interior (intervals 2 and 3) is high, resulting in a significant reduction in their numbers.

[0065] CO2 molecules can freely pass through the hydrophobic region at the entrance and eventually accumulate in the amine-functionalized region (region 3) at the deepest part of the pore, thus achieving efficient capture.

[0066] Step 5: Synthesize the guiding output.

[0067] Based on the optimal gradient functionalization scheme determined by the above simulations, this application outputs the following synthesis guidelines: Base-COF: The borate ester condensation reaction system corresponding to Base-COF is adopted.

[0068] Gradient functionalization implementation strategy: adopt the "step-by-step synthesis and post-modification" strategy.

[0069] 1) First, synthesize a COF intermediate containing unreacted aldehyde groups.

[0070] 2) First step modification: Excess tert-butylamine is used to react with the aldehyde groups at both ends of the COF channel under mild conditions. Due to the size of the reagent molecules and diffusion limitations, hydrophobic modification is mainly formed in the entrance region (interval 1).

[0071] 3) Second step modification: After thorough washing, ethylenediamine is used to react with the remaining aldehyde groups inside the pores under more vigorous conditions to form amine modification in the deeper region (region 3). By controlling the reaction time and reagent concentration, the unmodified transition region of region 2 can be achieved.

[0072] This embodiment demonstrates that, through the gradient functionalization design method, a COF structure design scheme optimized for high temperature and high humidity environments at the molecular level was successfully obtained. Its comprehensive performance exceeds that of traditional homogeneous modified materials, providing a concrete and feasible material design blueprint for solving the practical problem of CO2 capture on offshore natural gas platforms.

[0073] See Figure 2 This application also provides a system for optimizing the CO2 adsorption performance of COF materials based on molecular simulation. This system is used to implement the method for optimizing the CO2 adsorption performance of COF materials based on molecular simulation as described in the above embodiments. It includes: a material and operating condition definition module 101, a gradient model construction module 102, an efficiency index calculation module 103, an iterative optimization module 104, and a verification and output module 105 connected in sequence. The material and operating condition definition module is used to select a basic COF material with through-holes and define the operating conditions required for simulation. The gradient model construction module is used to construct candidate models of gradient-modified molecular models based on the selected COF material and the required operating conditions for simulation. The efficiency index calculation module is used to calculate the efficiency index using molecular simulation based on the candidate models and quantify their comprehensive adsorption performance under anti-interference conditions. The iterative optimization module is used to perform iterative optimization by changing the gradient design parameters, screen out optimized gradient-modified molecular models, and obtain optimized gradient schemes. The verification and output module is used to dynamically simulate the optimized gradient schemes, verify the effectiveness of the gradient function, and output a guidance manual.

[0074] Based on the above technical solutions, this application provides a method and system for optimizing the CO2 adsorption performance of COF materials based on molecular simulation. The method includes the following steps: Step S1, selecting a basic COF material with through-holes and defining the operating conditions required for simulation; Step S2, constructing candidate models of gradient-modified molecular models based on the selected COF material and the operating conditions required for simulation; Step S3, calculating the performance index using molecular simulation based on the candidate models and quantifying their comprehensive adsorption performance under anti-interference conditions; Step S4, iteratively optimizing by changing the gradient design parameters, selecting the optimized gradient-modified molecular model, and obtaining the optimized gradient scheme; Step S5, dynamically simulating the optimized gradient scheme, verifying the effect of the gradient function, and outputting a guidance manual.

[0075] This application constructs a gradient functionalized structure from hydrophobic domains to high-affinity domains, enabling COF materials to exhibit excellent anti-interference performance when facing high-temperature and high-humidity mixed gases. The high-density hydrophobic modification at the pore inlet effectively blocks the penetration of water molecules into the pore interior, reducing the competitive adsorption of water molecules by internal high-affinity sites. This allows the active sites inside the material dedicated to CO2 adsorption to remain clean and efficient in humid environments. Therefore, the material designed according to this method exhibits a more stable adsorption capacity in practical applications, reduces the pretreatment requirements for deep drying of the feed gas, simplifies the process flow, and reduces operating costs.

[0076] This application achieves precise control over the diffusion path and adsorption sites of gas molecules through gradient design guided by molecular simulation. The hydrophobic inlet region repels water molecules while offering minimal obstruction to smaller CO2 molecules, allowing them to rapidly penetrate deep into the pores. Meanwhile, the dense high-affinity functional groups deep within the pores strongly capture CO2, ensuring high adsorption selectivity. This synergistic mechanism of rapid inlet passage and strong internal capture enables the material to maintain high CO2 / CH4 selectivity without sacrificing its adsorption kinetics. The resulting material exhibits a faster adsorption rate and more efficient site utilization, thereby enabling the adsorption tower device to achieve higher processing efficiency in the periodic adsorption-desorption cycle.

[0077] Those skilled in the art will understand that the above-described embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this application. Any person skilled in the art can make their own modifications and alterations without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A method for optimizing the CO2 adsorption performance of COF materials based on molecular simulation, characterized in that, Includes the following steps: Step S1: Select a basic COF material with a straight channel and define the operating conditions required for simulation; Step S2: Based on the selected COF material and the operating conditions required for simulation, construct candidate models for gradient-modified molecular models; Step S3: Based on the candidate model, use molecular simulation to calculate the performance index and quantify its comprehensive adsorption performance under anti-interference conditions; Step S4: By changing the gradient design parameters, iterative optimization is performed to select the optimal gradient-modified molecular model and obtain the optimal gradient scheme. Step S5: Perform dynamic simulation on the optimized gradient scheme to verify the effect of the gradient function and output the instruction manual.

2. The method for optimizing the CO2 adsorption performance of COF materials based on molecular simulation according to claim 1, characterized in that, Select a base COF material with a straight channel and define the operating conditions required for simulation, including: A basic COF model with a one-dimensional through-hole structure is selected, and the atomic coordinates, bonding relationships, and lattice parameters of the basic COF model are used as the initial input structure for the simulation. Define the environmental parameters for the high temperature, high humidity, and mixed gas conditions required for the simulation to reflect the harsh conditions of the offshore platform pretreatment unit.

3. The method for optimizing the CO2 adsorption performance of COF materials based on molecular simulation according to claim 2, characterized in that, The basic COF model includes a model that mimics COF-1, with pore sizes between 1.5 nm and 3.0 nm.

4. The method for optimizing the CO2 adsorption performance of COF materials based on molecular simulation according to claim 1, characterized in that, Based on the selected COF material and the operating conditions required for the simulation, candidate models for gradient-modified molecular models are constructed, including: On the selected basic COF framework, the axis of its channel is defined as the Z direction; the entire channel is divided into N consecutive intervals along the Z axis, each interval representing a domain with a different degree of functionalization. Define different functional group modification strategies for each interval i; In molecular simulation software, by replacing or adding atoms, a COF crystal model with a gradient functionalization distribution, from the strongly hydrophobic functional region at the inlet to the high CO2 affinity functional region inside, is constructed as a candidate model.

5. The method for optimizing the CO2 adsorption performance of COF materials based on molecular simulation according to claim 4, characterized in that, Different functional group modification strategies are defined for each interval i, including: For the interval i=1: High-density hydrophobic functional groups are used for modification, and the modification density is... Set to maximum value ; For the middle interval Density of functional group modifications from Decrease linearly or exponentially to a lower value; For the interval i=N: Modification is performed using functional groups with a strong affinity for CO2, with a density set to... .

6. The method for optimizing the CO2 adsorption performance of COF materials based on molecular simulation according to claim 1, characterized in that, The performance indicators include: the material's CO2 adsorption capacity, selectivity, and water adsorption capacity; Performance metrics were calculated using molecular simulations, including: Using the giant canonical Monte Carlo molecular simulation method, the basic COF material defined in step S1 was subjected to adsorption simulation with the candidate model constructed in step S2 under defined operating conditions. After the simulation reached equilibrium, the absolute adsorption amount of CO2 in the COF material was statistically analyzed. The absolute adsorption capacity of water molecules in COF materials And calculate the CO2 / CH4 selectivity. ; Define the gradient functional synergistic efficacy index This is used to quantify the overall performance of gradient design under harsh operating conditions. The calculation formula is as follows: (Calculated in the simulation results analysis step) In the formula, and These represent the adsorption amounts of CO2 and H2O, respectively. This refers to the selectivity of CO2 for CH4; It is a positive number between 0.01 and 0.1, used to prevent the denominator from being zero.

7. The method for optimizing the CO2 adsorption performance of COF materials based on molecular simulation according to claim 1, characterized in that, By changing the gradient design parameters and performing iterative optimization, optimized gradient-modified molecular models are selected, resulting in optimized gradient schemes, including: By changing the gradient functionalization parameters in step S2, new candidate models are generated. The changed parameters include, but are not limited to: the number of gradient intervals N; the combination of functional group types in each interval; and the modification density distribution curve of functional groups in each interval. For each new candidate model, repeat step S3 to calculate its corresponding synergistic efficiency index. ; Comparing all candidate models Value, selection The candidate model that reaches the maximum value is the optimized gradient-modified molecular model. The gradient functional parameter corresponding to the maximum value is determined as the optimized gradient scheme.

8. The method for optimizing the CO2 adsorption performance of COF materials based on molecular simulation according to claim 1, characterized in that, Dynamic simulations are performed on the optimized gradient scheme to verify the effectiveness of the gradient function, including: Additional molecular dynamics simulations were performed on the optimized gradient-modified molecular model for several nanoseconds to observe the dynamic behavior of gas molecules within the pores. The effectiveness of the gradient function was verified by analyzing trajectory files from molecular dynamics simulations.

9. The method for optimizing the CO2 adsorption performance of COF materials based on molecular simulation according to claim 1, characterized in that, Verify the effectiveness of the gradient feature, including: Observe whether water molecules are indeed confined to the hydrophobic region at the entrance of the pore and have difficulty diffusing into the interior of the pore; Observe whether CO2 molecules can successfully pass through the hydrophobic region at the entrance and accumulate in the high-affinity regions of amino / amidinyl groups deep within the pores.

10. A system for optimizing the CO2 adsorption performance of COF materials based on molecular simulation, the system being used to implement the method for optimizing the CO2 adsorption performance of COF materials based on molecular simulation as described in any one of claims 1 to 9, characterized in that, include: The module is sequentially connected to the following modules: material and working condition definition module, gradient model construction module, performance index calculation module, iterative optimization module, and verification and output module; among them... The material and operating condition definition module is used to select the basic COF material with a straight channel and to define the operating conditions required for simulation. The gradient model building module is used to build candidate models for gradient-modified molecular models based on the selected COF material and the operating conditions required for the simulation. The efficiency index calculation module is used to calculate the efficiency index using molecular simulation based on the candidate model, and to quantify its comprehensive adsorption performance under anti-interference conditions. The iterative optimization module is used to perform iterative optimization by changing the gradient design parameters, select the optimized gradient-modified molecular model, and obtain the optimized gradient scheme. The verification and output module is used to dynamically simulate the optimized gradient scheme, verify the effect of the gradient function, and output a guidance manual.

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